If really worried about performance, the fasthttp package is much faster than the one included in go.

"In short, fasthttp server is up to 10 times faster than net/http."

https://github.com/valyala/fasthttp

The headline says "20%", which would imply that a "similar slowdown" for a 100 milliseconds response would bring it to 120 milliseconds.

But what is actually happening is that every request takes roughly an extra 0.04 milliseconds, so the time might go up to 100.04 milliseconds, probably within margin of error for most services anyway.